The present invention relates to a flow equalizer device for a commercial milk dispenser system which provides palatable milk by dispensing simultaneously into a receptacle a combination of whole milk and reconstituted skim milk.
It is well know that a palatable milk substitute can be obtained by combining homogenized fluid milk and powdered skim milk. Such a combined product produces considerable savings, since an equal volume of powdered skim milk is significantly cheaper than homogenized, partly skim (e.g. 2%) or skim milk. While in a domestic environment there is no problem in blending powdered skim milk with homogenized fluid milk to produce such a palatable whole milk substitute, problems develop in applying this practice to large scale institutions. Essentially, labour costs eliminate the cost savings which would otherwise result. As well, previously there has not been an efficient, sanitary method of mixing such milk.
Conventionally, for large institutions, about the only way of producing such a palatable milk substitute is to mix the powdered skim milk and water in proper proportions in a pail, portion the resultant mixture and add homogenized or partly skim milk.
There is presently available for commercial use in the marketplace powdered milk in a twenty liter capacity bag having a flexible outlet tube adaptable to commercial milk dispensers. The purchaser simply fills the bag with water prior to use. This eliminates the necessity of measuring water or powder, since the powder is in the right proportion in the bag for the size of the bag. Such bags however may have different sized outlet tubes and thus dispense their contents at differing flow rates.
Conventional gravity flow milk dispensers consist of insulated cabinets within which, usually, either a single or double compartment for holding milk is found. A front door provides access to the compartment or compartments within which one or more milk containers sit. In one form of such a milk dispenser, one or more cages sit within the compartment, each to hold, for example, a twenty liter milk bag having a flexible outlet tube at its bottom. A single liquid outlet controller having a mechanism for pinching the outlet tube from the milk bag within, is positioned in front of each compartment on the outside of the milk dispenser cabinet. The valve is handle-operated so that the consumer, by manipulating the handle, obtains the desired amount of milk in a glass or other receptacle positioned beneath that tube outlet. In double compartment dispensers, two such outlet controllers are provided, one for each container or cage. Milk is dispensed under gravity flow.
In my co-pending U.S. application Ser. No. 680,720, now U.S. Pat. No. 4,651,898, a liquid dispenser outlet controller is described and illustrated which provides simultaneous dispensing, under gravity flow and combination in a receptacle, of proper (preferably almost equal) proportions of homogenized whole milk and reconstituted powdered skim milk. These two types of milk are held in separate bags with their own, individual outlet tubes. This controller consists of a channel defined by walls within which channel outlet tubes from each of the liquid containers pass. Retainer means are associated with the channel to maintain the positioning of the tubes within the channel a similar distance with respect to one of the walls of the channel. A tube pinch valve having a surface parallel to that wall of the channel is positioned on the opposite side of the tubes with respect to that wall. Movement of this valve by the operator causes the pinch valve surface to move in parallel fashion with respect to that wall between a position proximal to, but spaced from the wall to pinch off simultaneously the flow of liquid through the tubes in a position more distant from the wall which permits unobstructed simultaneous gravity flow of liquid through each of the tubes.
Such an outlet controller device may be used in combination with a conventional gravity flow milk dispenser cabinet or with any other appropriate structure for holding the bags of whole milk and reconstituted powdered skim milk.
One of the problems which has been experienced in using such a device arises because of the previously-mentioned fact that not all of the flexible tubes of the milk bags are of the same cross-sectional diameter. Hence flow rates between the bag of whole milk and the bag of reconstituted powdered skim milk may differ. This may become significant since ideally the powdered skim milk bag should empty just before the whole milk bag. In this way a constant quality and good flavour of the milk dispensed by the system is achieved. If, on the other hand, the whole milk bag were to be emptied first, reconstituted powdered skim milk, which has an inferior flavour to that of the whole milk, would continue to be dispensed alone, resulting in a less palatable product. As well, for an acceptably good flavour of product, it is important to equalize, as much as possible, the flow rates of the milk as it is dispensed through each of the outlet tubes. When bags of whole and reconstituted powdered skim milk of similar volume of contents are used, the flow rates should thus be similar or the flow rate of the powdered skim milk should be slightly greater than that of the whole milk (to ensure emptying of the reconstituted powdered skim milk bag first).
One solution which one might think of for this problem would be to pass the outlet tube having the higher flow rate through a smaller hole, for example in the retainer means, to constrict the internal diameter of the outlet tube at one point and thereby restrict the flow. This would produce an unpredictable flow rate however since the same diameter tube will crimp differently from one time to the next when passed through such a constricting hole.
Of general background interest to the present invention are U.S. Pat. No. 4,434,963 of Russell issued Mar. 6, 1984 and U.S. Pat. No. 3,429,549 of Swanson issued Feb. 25, 1969. The Russell U.S. patent describes and illustrates a side clamp for flexible medical tubing that includes a slot dividing the clamp into two sides, the slot having a wide area where full flow through the tube is permitted and a narrow area where complete closure of the tube is achieved. The two halves of the clamp are capable of flexure towards and away from each other to facilitate disposition of the tubing within the narrow portion of the slot. The Swanson reference describes and illustrates a metering device circumscribing a flexible tube and having a bore which may be adjustably flattened to constrict the flow through the tube. Neither of these devices would be practical for use in conjunction with a milk dispenser outlet controller device of the type in question.
It is an object of the present invention to provide a device which can be used in conjunction with the aforementioned type of liquid dispenser outlet controller and can be applied to one outlet tube to approximate or equalize uniformly the flow rate through that outlet tube with that of the other outlet tube.